Apertured webs are utilized in a wide variety of industrial and consumer products. For example, apertured films or apertured nonwovens are known for use in disposable absorbent articles such as disposable diapers and feminine hygiene articles such as sanitary napkins, and the like. Such articles typically have a fluid pervious topsheet, a fluid impervious breathable backsheet, and an absorbent core disposed between the topsheet and the backsheet. An apertured film can be made to form a fluid pervious topsheet and/or the fluid impervious breathable backsheet.
U.S. Patent Application No. 2006/0087053 published Apr. 27, 2006 discloses a method for making apertures in a precursor web by moving the web material through a nip of the counter-rotating, intermeshing rollers, wherein a first roller comprises circumferentially-extending ridges and grooves, and a second roller comprises teeth being tapered from a base to a tip which are joined to the second roller at the base. The base of the tooth has a cross-sectional length dimension greater than a cross-sectional width dimension. Apertures are formed in the precursor web material as the teeth on one of the rollers intermesh with grooves on the other of the rollers. The process provides an efficient and cost effective means of forming apertures in a web; however, the size and shape of the apertures is limited by the shape and orientation of the teeth in the second roller as well as the orientation of the long chain molecules forming the film. For instance, extruded films have molecular orientations where a majority of the long chain molecules are oriented in the machine direction, which for an extruded film is the path that the film follows through the extrusion process. The cross sectional length of the teeth on the second roller of the counter rotating rollers is also aligned in the machine direction. As a result, when forming apertures in extruded films, the process tends to produce apertures resembling slits. Although slits may be acceptable for some applications, apertures resembling oval holes are typically preferred.
Accordingly, there is a need for a process for producing apertures in a film or film nonwoven laminate that can overcome the effect of film molecular orientation and produce apertures resembling oval holes rather than slits.